.linear1 {
	display : block;
	width : 400;
	height : 200;
	background-image : linearGradient(left,[
		[alpha(yellow,0.4),	0.4],
		[red, 		1]
	]);
}

function bottomRightAngle(w,h) {
	return -Math.floor(Math.tan(h/w)*180/Math.PI)+'deg';	
}

var w = 400;
var h = 200;
.linear2 {
	display : block;
	width : w;
	height : h;
	// warning angled gradient is not supported by IOS
	background-image : linearGradient(bottomRightAngle(w,h), [
		[aqua, 0],
		[blue, 0.5],
		[rgba(0, 0, 255, 0), 1],
	]);
}

function rainbowGradient(color) {
	var num = 6;
	var stops = [], shift;
	for (var i=0;i<=num;i++) {
		shift = i/num;
		stops.push([ blueshift(color,shift), shift ]);
	}
	return stops;
}

.linear3 {
	display : block;
	width : 400;
	height : 200;
	background-image : linearGradient(topLeft,rainbowGradient(rgb(255,255,0)));
}